South Africa

The study is focused on the technology and manipulation of production strategies for the cultivation of biomass from four strains of microalgae. Species of microalgae studied are: Chlorella vulgaris Dunaliella Scenedesmus quadricauda and Synechococcus spp. The effects of the rate and amount of CO₂ removal from the atmosphere and sequestration with dissolved oxygen on lipid production from accumulated biomass were studied. Also the rate of sequestration of both total and dissolved carbon was  investigated. Daily measurements of total organic and inorganic carbon sequestrated optical densities proximate analysis and kinetic parameters of the growing and cultivated microalga were monitored and carried out during the two phases of cultivation: dark and light phases. The values of maximum rate of carbon (IV) oxide removed rmax varied from 11.73 mg L ^-1 min ^-1 to 18.84 mg L ^-1 min ^-1 from Chlorella vulgaris to Synechoccocus spp. Important parameters such as biomass productivity maximum pH values obtained at cultivation lipid content of the produced biomass and the hydraulic detection time for all four strains of microalgae were considered and presented in comparison and with their individual and collective effects. The ratios of the rate of CO₂ absorption constant and the constant for the CO₂ desorption rate (k1/k2) occurred highest in Dunaliella suggesting that with a high uptake of CO₂ the algal strain is more effective in CO₂ CO2 sequestration. The best biomass producer in this study was the C. vulgaris (Xmax = 5400 mg L^-1 and Px = 35.1 mg L h ^-1) where biomass productivity is Px and the maximum cellular concentration is Xmax. C. vulgaris has the highest lipids productivity of 27% while Synechoccocus has the least (11.72%). In general biomass productivity may be inversely related; this fact may be explained by greater metabolic involvement of lipid biosynthesis. This pioneer study may be advanced further to developing models for strategic manipulation and optimisation approach in micro algal biomass cultivation.

Concerns about greenhouse gases as well as the price and security of oil supply have acted as a spur to sustainable automobile development. The hydrogen fuel cells electric vehicle (HFCEV) is generally recognised by leading automobile manufacturers and scientists as one of the optimum technologies for long-term future low carbon vehicle. In a typical HFCEV power train a DC–DC converter is required to balance the voltage difference between the fuel cells (FCs) stack and batteries. However research shows that a considerable amount of energy generated by the hydrogen FCs stack is deplete during this conversion process as heat. This experiment aims to improve the power train efficiency by eliminating the DC–DC converter by finding the best combination of FC stack and batteries matching the size and capacity of the electrical components.

Biofuel a cost-effective safe and environmentally benign fuel produced from renewable sources has been accepted as a sustainable replacement and a panacea for the damaging effects of the exploration for and consumption of fossil-based fuels. The current work examines the classification generation and utilization of biofuels particularly in internal combustion engine (ICE) applications. Biofuels are classified according to their physical state technology maturity the generation of feedstock and the generation of products. The methods of production and the advantages of the application of biogas bioalcohol and hydrogen in spark ignition engines as well as biodiesel Fischer– Tropsch fuel and dimethyl ether in compression ignition engines in terms of engine performance and emission are highlighted. The generation of biofuels from waste helps in waste minimization proper waste disposal and sanitation. The utilization of biofuels in ICEs improves engine performance and mitigates the emission of poisonous gases. There is a need for appropriate policy frameworks to promote commercial production and seamless deployment of these biofuels for transportation applications with a view to guaranteeing energy security.

There is a great deal of knowledge and experience on the safe handling of hydrogen and the safe operation and management of hydrogen systems in South Africa. This knowledge and experience mostly sits within large gas supply companies and other large producers and consumers of hydrogen. However there appears to be less experience leading to a level of discomfort within regulatory bodies such as provincial and municipal fire departments and the national standards association. This compounded by a national policy of disallowing gas cylinders indoors has resulted in delays and indeed stalling in the process of obtaining permission to operate laboratories such as those of the national hydrogen programme HySA. In an effort to break this impasse two workshops were organised by HySA. The first was held at the CSIR’s facilities in Pretoria in October 2016. The second was held at the campus of the University of the Western Cape in Cape Town in May 2018. Four international experts and local experts in hydrogen regulations codes standards and safety addressed the 50-strong South African audiences via 5-way videoconferencing. This proved to be a very powerful tool to educate the audience and in particular the Tshwane (Pretoria) and Western Cape Fire Departments on the real issues risks and safety of hydrogen. The paper describes the South African Hydrogen RCS landscape the organisation and running of the workshops and the outputs achieved.

One of the focus areas in the heavy-duty transport industry globally is de-carbonization of trucks dozers shovels semi-trucks buses etc. Hydrogen fuel cells (FCs) technology is one considered solution for the industry due to its zero-emissions its MW scalability and capacity to store large amounts of energy for long duration continuous power operation. Underground deep mines is another option for deployment and operation of hydrogen FCs. Benefits include lower emissions improved health comfort and safety as well as reduced operating costs. Underground mining trucks loaders and other machines have power ratings up to 750 kW which proves difficult for battery and tethered electric energy. Hydrogen FCs have the ability to overcome these power and energy storage limitations. The risks and technologies associated with delivering storing and using hydrogen underground first need to be investigated and proven safe. This work presents the design construction and operation of a mining ventilation test facility (VTF) at the North-West University in South Africa that aims to quantify the risk of hydrogen in confined ventilated environments. Initial work has been conducted on measuring concentrations of hydrogen released in the temporary ventilation site and is discussed.

Magnesium hydride owns the largest share of publications on solid materials for hydrogen storage. The “Magnesium group” of international experts contributing to IEA Task 32 “Hydrogen Based Energy Storage” recently published two review papers presenting the activities of the group focused on magnesium hydride based materials and on Mg based compounds for hydrogen and energy storage. This review article not only overviews the latest activities on both fundamental aspects of Mg-based hydrides and their applications but also presents a historic overview on the topic and outlines projected future developments. Particular attention is paid to the theoretical and experimental studies of Mg-H system at extreme pressures kinetics and thermodynamics of the systems based on MgH₂ nanostructuring new Mg-based compounds and novel composites and catalysis in the Mg based H storage systems. Finally thermal energy storage and upscaled H storage systems accommodating MgH₂ are presented.

Metal hydrides are known as a potential efficient low-risk option for high-density hydrogen storage since the late 1970s. In this paper the present status and the future perspectives of the use of metal hydrides for hydrogen storage are discussed. Since the early 1990s interstitial metal hydrides are known as base materials for Ni – metal hydride rechargeable batteries. For hydrogen storage metal hydride systems have been developed in the 2010s [1] for use in emergency or backup power units i. e. for stationary applications.<br/>With the development and completion of the first submarines of the U212 A series by HDW (now Thyssen Krupp Marine Systems) in 2003 and its export class U214 in 2004 the use of metal hydrides for hydrogen storage in mobile applications has been established with new application fields coming into focus.<br/>In the last decades a huge number of new intermetallic and partially covalent hydrogen absorbing compounds has been identified and partly more partly less extensively characterized.<br/>In addition based on the thermodynamic properties of metal hydrides this class of materials gives the opportunity to develop a new hydrogen compression technology. They allow the direct conversion from thermal energy into the compression of hydrogen gas without the need of any moving parts. Such compressors have been developed and are nowadays commercially available for pressures up to 200 bar. Metal hydride based compressors for higher pressures are under development. Moreover storage systems consisting of the combination of metal hydrides and high-pressure vessels have been proposed as a realistic solution for on-board hydrogen storage on fuel cell vehicles.<br/>In the frame of the “Hydrogen Storage Systems for Mobile and Stationary Applications” Group in the International Energy Agency (IEA) Hydrogen Task 32 “Hydrogen-based energy storage” different compounds have been and will be scaled-up in the near future and tested in the range of 500 g to several hundred kg for use in hydrogen storage applications.

Biogas is a renewable feedstock that can be used to produce hydrogen through the decomposition of biomethane. However the economics of the process are not well studied and understood especially in cases where solid carbons are also produced and which have a detrimental effect on the performance of the catalysts. The scale as well as product diversification of a biogas plant to produce hydrogen and other value-added carbons plays a crucial role in determining the feasibility of biogasto-hydrogen projects. Through a techno-economic study using the discounted cash flow method it has been shown that there are no feasible sizes of plants that can produce hydrogen at the target price of USD 3/kg or lower. However for self-funded anaerobic digestor plants retrofitting modular units for hydrogen production would only make financial sense at biogas production capacities of more than 412 m3/h. A sensitivity analysis has also shown that the cost competitiveness is dependent on the type of carbon formed and low-grade carbon black has a negative effect on economic feasibility. Hydrogen produced from biogas would thus not be able to compete with grey hydrogen production but rather with current green hydrogen production costs.

One of the many technical benefits of green diesel (GD) is its ability to be oxygenated lubricated and adopted in diesel engines without requiring hardware modifications. The inability of GD to reduce exhaust tail emissions and its poor performance in endurance tests have spurred researchers to look for new clean fuels. Improving gasohol/hydrogen blend (GHB) spark ignition is critical to its long-term viability and accurate demand forecasting. This study employed the Response Surface Methodology (RSM) to identify the appropriate GHB and engine speed (ES) for efficient performance and lower emissions in a GHB engine. The RSM model output variables included brake specific fuel consumption (BSFC) brake thermal efficiency (BTE) hydrocarbon (HC) carbon dioxide (CO2) and carbon monoxide (CO) while the input variables included ES and GHB. The Analysis of Variance-assisted RSM revealed that the most affected responses are BSFC and BTE. Based on the desirability criteria the best values for the GHB and the ES were determined to be 20% and 1500 rpm respectively while the validation between experimental and numerical results was calculated to be 4.82. As a result the RSM is a useful tool for predicting the optimal GHB and ES for optimizing spark-ignition engine characteristics and ensuring benign environment.

The power and transport sectors are responsible for significant emissions of greenhouse gases. Therefore it is imperative that substantial efforts are directed towards the decarbonisation of these industries. This study establishes a combined-solar-wind system's economic and technical practicality for producing hydrogen for an onsite hydrogen refuelling station (HRS) and electricity to meet peak demand. To minimise the levelised cost of electricity and maximise the system's reliability at different commercial locations in South Africa the dual-objective optimisation sizing is carried out using Mixed Integer Quadratic Constrained Programming (MICQP) model and was executed with an Advanced Multi-dimensional Modelling System (AIMMS) [61] [62]. The levelised costs of electricity and hydrogen at Johannesburg Pretoria and Cape Town for 2 MW grid export benchmark are 74.2 $/MWh/5.85 $/kg 76.3 $/MWh/5.97 $/kg and 50 $/MWh/4.45 $/kg respectively. The CO₂ equivalent emissions (tonnes) are 54000 55800 59000 and the corresponding carbon taxes ($) avoided for the locations are 432100 446200 and 472000 for Johannesburg Pretoria and Cape Town respectively. The results of the framework show that it can be adopted as a viable and fossil-free replacement for conventional peaking generators.